A bill that would classify excess heat produced by manufacturing processes as a renewable resource recently passed the state Assembly with broad support from some of Wisconsin’s biggest industries.

Electric utilities and retail electric cooperatives are currently held to “renewable portfolio standards,” which require a certain percentage of the electricity they sell to retail customers to come from renewable resources.

These groups can use renewable resource credits -- which they can create themselves or buy from others -- to meet the required percentage. These RRCs are created when electricity is produced from a renewable resource like solar, wind, geothermal, biomass and others.

Utilities and co-ops, as well as their customers and members, can also get RRCs based on the use of renewable resources, to the degree that their use displaces electricity derived from conventional resources.

The bill, which passed the Senate earlier this year, would place waste heat in the same category as wind and solar with respect to the RRC program. It goes now to Gov. Scott Walker for approval.

Thermal energy can often be harnessed and put to use, rather than dissipating into the atmosphere after being vented out of a facility.

“Wisconsin has one of the most manufacturing-dependent economies in the country.” said Todd Stuart, executive director of the Wisconsin Industrial Energy Group. “This bill is intended to spur capital investment, save on energy costs and create or retain jobs for Wisconsin’s manufacturing base."

In a foundry, paper mill, or other production business, a lot of extra heat is produced, which is often just released into the air. But some companies already use this thermal energy to generate electricity or offset the use of other resources.

For example, Waupaca Foundry, a producer of iron products for a variety of industries, uses a closed-loop heat recovery system at a plant in Waupaca.

According to Bryan Esch, chief sustainability officer for Waupaca Foundry, the system provides nearly all of the building’s heat in winter and heats up water in the facility year-round.

The heat-capture project, which earned Waupaca Foundry the Governor’s Award for Excellence in Environmental Performance in 2009, has also resulted in an annual reduction of 4,600 metric tons of carbon dioxide, Esch said.

If the waste heat recovery bill gets final approval, it could encourage more companies to implement these kinds of projects, according to Lucas Vebber, general counsel and director of environmental and energy policy for Wisconsin Manufacturers and Commerce.

He said the bill introduces “a simple change” that around 19 other states have already enacted. And with manufacturing and the paper industry dominating the Wisconsin economy, he says this reform will have “positive value” for the state.

According to Nick George, president of the Midwest Food Processors Association, the bill will benefit the food processing industry as well.

Food processors are very energy intensive, he said, using “a lot of electricity and a lot of natural gas” to heat up various products.

“The whole food industry in particular is under a lot of pressure to demonstrate to customers that they’re doing energy conservation, water conservation -- more sustainable works,” George said, adding that this bill will help support those efforts.

MWFPA, along with WMC, WIEG, the Wisconsin Paper Council and the Wisconsin Cast Metals Association supported the bill in a coalition of the most energy-intensive industries in the state.